[游戏开发]Unity使用UGUI的Image在UI两个对象之间画线

效果：

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class UILink : MonoBehaviour
{
    public GameObject Line;
    public Transform mapContent;
    public RawImage BeginUI;
    public RawImage EndUI;
    public RawImage EndUI2;
  
    Vector2 BeginPos;
    Vector2 targetPos;
    Vector2 targetPos2;
    private void Start()
    {
        BeginPos = BeginUI.rectTransform.localPosition;
        targetPos = EndUI.rectTransform.localPosition;
        targetPos2 = EndUI2.rectTransform.localPosition;
        CreateLine(BeginPos, targetPos);
        CreateLine(targetPos, targetPos2);
    }
    /// <summary>
    /// 创建一条两点之间的线
    /// </summary>
    /// <param name="start">起始点</param>
    /// <param name="end">结束点</param>
    public void CreateLine(Vector2 start, Vector2 end)
    {
        //实例化需要显示的线段图片pfb
        GameObject line = Instantiate(Line);
        line.transform.SetParent(mapContent);
        RectTransform rect = line.GetComponent<RectTransform>();
        //设置位置和角度
        rect.localPosition = GetBetweenPoint(start, end);
        rect.localRotation = Quaternion.AngleAxis(-GetAngle(start, end), Vector3.forward);
        rect.localScale = new Vector3(20, 1, 1);
        //设置线段图片大小
        var distance = Vector2.Distance(end, start);
        rect.sizeDelta = new Vector2(5, Math.Max(1, distance));
        //调整显示层级
        line.transform.SetAsFirstSibling();
    }

    /// <summary>
    /// 获取两个坐标点之间的夹角
    /// </summary>
    /// <param name="start">起始点</param>
    /// <param name="end">结束点</param>
    /// <returns></returns>
    public float GetAngle(Vector2 start, Vector2 end)
    {
        var dir = end - start;
        var dirV2 = new Vector2(dir.x, dir.y);
        var angle = Vector2.SignedAngle(dirV2, Vector2.down);
        return angle;
    }

    /// <summary>
    /// 获取上下相邻两个坐标点中间的坐标点
    /// </summary>
    /// <param name="start">起始点</param>
    /// <param name="end">结束点</param>
    /// <returns></returns>
    private Vector2 GetBetweenPoint(Vector2 start, Vector2 end)
    {
        //两点之间垂直距离
        float distance = end.y - start.y;
        float y = start.y + distance / 2;
        float x = start.x;

        if (start.x != end.x)
        {
            //斜率值
            float k = (end.y - start.y) / (end.x - start.x);
            //根据公式 y = kx + b ， 求b
            float b = start.y - k * start.x;
            x = (y - b) / k;
        }

        Vector2 point = new Vector2(x, y);
        return point;
    }

}